1. Field of the Invention
The present invention relates generally to fluid flow control apparatus, and more particularly relates to apparatus for detecting leakage or other malfunctions in a shutoff valve installed in a pipe through which pressurized fluid may be flowed.
2. Description of Related Art
Unattended control valve malfunctions, such as leakage, in pressurized piping systems in remote locations can often cause significant damage and attendant repair costs until detected. Such damage can be a quite serious when the remote piping system is handling environmentally and/or health sensitive chemicals. For example, in automated systems, valves which leak in their closed positions, or stick in their open positions, can cause major overflowing of chemical tanks with which they are operatively associated.
Various valve malfunction detection systems have been previously been proposed, but typically suffer from a variety of problems, limitations and disadvantages including, for example, size limitations, the inability to detect very small amounts of valve leakage, the inability to distinguish between valve leakage and the failure of a valve to open or close, mechanical and electrical complexity, and/or a lack of overall fail safe operation.
It is accordingly an object of the present invention to provide an improved valve malfunction detection system which eliminates, or at least substantially reduces, the above-mentioned problems, limitations and disadvantages typically associated with conventional valve malfunction detection systems.